R. Martinez et al., IMPLICATIONS OF B-]S-GAMMA ON THE ANOMALOUS ELECTROMAGNETIC COUPLINGSOF GAUGE BOSONS AND QUARKS, Physics letters. Section B, 340(1-2), 1994, pp. 91-95
We reexamine the possible deviations from the standard model on the de
cay b --> s gamma within the context of an effective Lagrangian approa
ch. We consider dimension-6 operators which are SU(2)(L) X U(1)(Y) gau
ge invariant and contribute to this decay mode at tree- and one-loop l
evel. Using the recent results of the CLEO Collaboration on radiative
B decays, we get constraints on the anomalous electromagnetic coupling
s of the W boson and the quarks t, c, u. We get an improved constraint
on the anomalous magnetic moment of the quark t as compared to that o
btained with only U(1)(EM) gauge-invariant dimension-6 operators. As a
byproduct, we obtain also a bound on the decay width of t --> c gamma
.